And they promise this development will transform not just these towns, but Timor-Leste itself, bringing wealth, skilled jobs and development to the fledgling nation.

Analysts label this vision a pipe-dream, and the multinational companies that hold the rights to Greater Sunrise are unconvinced.

But Dili is pushing ahead. And this week it sent a very big signal that it remained determined, pledging almost half a billion dollars to buy a 30 per cent share in the Greater Sunrise consortium held by US company ConocoPhillips.

Timor-Leste's former president, Xanana Gusmao, is now set on convincing the other oil and gas giants with a stake in Greater Sunrise that Dili's vision can work.

It's a sudden and dramatic manoeuvre. But Timor-Leste knows it has to move quickly.

Right now, almost all of its revenue comes from oil and gas fields that could run dry in less than five years.

And the sovereign wealth fund the nation has built from its natural assets will not last forever. Experts predict it will dwindle to nothing well before 2030.

Why buy out Conoco?

If Timor-Leste wanted any chance of convincing the oil and gas giants to send LNG to Beaço, then it needed ConocoPhillips out of the picture.

Before the most recent move from Dili, exploration and exploitation rights for Greater Sunrise were held by four energy companies — Woodside, ConocoPhillips, Shell and Osaka Gas.

All four venture partners have been deeply sceptical about whether Timor-Leste's vision of a flourishing domestic LNG industry is viable.

But sources close to recent discussions have told the ABC ConocoPhillips has never looked like budging.

Just a pipedream?

First, building a pipeline to Timor-Leste poses formidable challenges.

It would have to cross an ocean trench called the Timor Trough, which plunges to depths of more than three kilometres.

One expert predicts it would have to be 75 per cent thicker than the heaviest pipeline ever built before — the Blue Stream, which runs across the Black Sea.

The oil and gas companies are also sceptical about whether Timor-Leste has the capacity to develop an industry from scratch.

Earlier this year, the UN Conciliation Commission published analysis which found Timor-Leste's proposal would only get off the ground with a government subsidy of about $7.7 billion.

That drew a furious response from Mr Gusmao, who called the assessment "shockingly superficial" and accused Canberra of colluding with the big energy companies to send the gas to Darwin instead of Beaço.

The future is now

The next six months will be crucial, and Australia will be watching the negotiations carefully.

Strictly speaking, the Federal Government is neutral on how the gas fields should be developed — but officials also doubt Timor-Leste's grand plan can become a reality.

That clearly frustrates Dili, which is using every bit of leverage it can get.

Some Timor-Leste Government figures have been quoted saying if they could not convince the energy companies to get on board, then they might turn to China to help them buy out the other partners and build the new pipeline.

Close observers say that is probably a negotiating tactic rather than a real live option.

But Australia is already wary about China's growing influence in Pacific Island nations, and the prospect of Timor-Leste taking on a massive soft loan from Beijing would concentrate minds in Canberra.

And there is no need to conjure nightmare scenarios — the current stalemate on Sunrise is already deeply worrying for both countries.

Timor-Leste is a poor country with a burgeoning population and few sources of cash. It desperately needs Greater Sunrise to fill coffers that will rapidly dwindle when the current reserves run dry.